Field of the Invention
The present invention relates to a laser processing apparatus performing laser processing on a workpiece such as a semiconductor wafer or the like.
Description of the Related Art
In a semiconductor device manufacturing process, a plurality of regions are partitioned by scheduled division lines arranged in a lattice manner on the top surface of a semiconductor wafer in substantially the shape of a disk, and devices such as ICs, LSIs, or the like are formed in the partitioned regions. The regions in which the devices are formed are then divided from each other by cutting the semiconductor wafer along the scheduled division lines. The individual semiconductor devices are thus manufactured. In addition, an optical device wafer formed by stacking light receiving elements such as photodiodes or the like or light emitting elements such as laser diodes or the like on the top surface of a sapphire substrate is also cut along scheduled division lines, and thereby divided into individual optical devices such as the photodiodes, the laser diodes, and the like, which are widely used in electric devices.
Proposed as a method for dividing a wafer such as a semiconductor wafer, an optical device wafer, or the like as described above along scheduled division lines is a method of forming laser-processed grooves by applying a laser beam having a wavelength capable of being absorbed by the wafer along the scheduled division lines formed on the wafer and thus performing ablation processing, and breaking the wafer along the laser-processed grooves (see for example Japanese Patent Laid-Open No. 2010-272697).